STOCKHOLM, SWEDEN (UroToday.com) - Studies suggest that lower castrate levels of testosterone, achieved with continuous androgen deprivation therapy (ADT), are associated with both superior survival and time to progression. High quality prospective evidence demonstrating the effect of testosterone levels on survival while on ADT is lacking. Dr. Laurence Klotz and colleagues hypothesized that for patients on continuous ADT, higher testosterone levels correlate with a reduced time to develop castration resistant disease and lower cancer specific survival. Patients receiving continuous ADT in the NCIC/SWOG/UKCCR PR7 study were analyzed to assess the relationship between the minimum, median, and maximum testosterone in the first year, and the time to androgen-independent progression (defined as a rising PSA > 4 with testosterone < 3.0 nm/l).
Among the 3 groups, there was a significant difference in time to hormone resistance, with median time to CRPC being not reached 6.4, and 4.2 years for the 3 groups, respectively. Patients with a median testosterone level > 0.7 nm/l had a significantly increased risk of developing castration resistance (HR 1.41). For serum testosterone levels > 1.7, the risk of castration resistance was even greater (HR 1.91). In patients with a higher median testosterone level, there was a reduction in the time from hormone resistance to prostate cancer death.
A low nadir serum testosterone (< 0.7 nm/l) in men on continuous ADT for biochemical recurrence of prostate cancer correlates with an improved duration of response to ADT. Dr. Klotz recommended regular assessment of serum testosterone in such patients, with subsequent ADT modifications to ensure levels < 0.7 nm/l are achieved.
Presented by Laurence Klotz at the 29th Annual European Association of Urology (EAU) Congress - April 11 - 15, 2014 - Stockholmsmässan - Stockholm, Sweden.
Sunnybrook Health Sciences Centre, Department of Urology, Toronto, Canada
Written by Jeffrey J. Tomaszewski, MD, medical writer for UroToday.com
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